As I continue reading and re-reading about all the different breeds, I often come across the term "mountain" type and I notice that most of them are category 1 dogs. The other dogs, the ones I think of as being more of guard dog type dogs are mostly in category 2. In most cases, the difference in appearance and personalities of the dogs between the two categories is pronounced. The mountain types tend to have larger heads, longer, shaggier coats, many are shepherds and for the most part seem to be gentler than the cat 2 dogs who have smaller heads, smoother, shorter coats and generally seem to have more aggressive tendencies for guarding. Does "mountain" refer to their places of origin (mountain herding, for example) or does it refer to something they possess (or don't possess) genetically that the cat 2 dogs don't (or do/vice versa)? I guess what I'm asking is that even though the difference in appearance is generally obvious, both categories are molossers and are relatives. How can they be so different in appearance and what, exactly, does "mountain type" refer to? I imagine that dog genetics is a HUGE field of study so I'm not expecting a lot of detail or intricate explanation - just basically what does "mountain" refer to and why do the two categories look so different? I had no idea there were so many of these breeds until I came upon this site. The encyclopedia of profiles is impressive, to say the least. The inclusion of the extinct, rare, and exotic breeds in the encyclopedia is VERY informative and interesting .